There are currently a variety of technologies for conducting communications between fixed and/or mobile communication stations. Some communication technologies are not compatible with others, which can prevent two communication stations from communicating with each other. This incompatibility is particularly problematic for emergency workers and other first responders. Many fire departments and police agencies operate private land mobile radio (LMR) systems for intra-department communications. These private systems typically provide push-to-talk (PTT) communications over VHF and UHF frequency bands and do not interoperate with each other or with other communication systems. Unlike conventional circuit-switched or interconnect voice communication technologies, push-to-talk systems provide half-duplex communications, and are typically implemented in a proprietary manner. Accordingly, during an emergency situation a police agency may not be able to communicate with a fire department due to the use of different land mobile radio systems.
JPS Communications, Inc., provides a modular interface/interconnect system known as the ACU-1000. This system can interconnect communications between a land mobile radio system, public switched telephone network (PSTN), satellite communication system, cellular communication system and/or an iDEN push-to-talk and interconnect communication network. The ACU-1000 requires a hardware interface module for each communication technology that is to be supported for interconnection of communication stations. Each interface module includes hardware specifically designed for a particular communication technology. Accordingly, an interface module must be ordered from JPS Communications, Inc. and then installed in the ACU-1000 system to support a particular communication technology.
One problem with the ACU-1000 is that if a particular interface module is not already installed in the system, the system cannot support that communication technology. This is particularly problematic for supporting emergency personnel because it may not be known in advance which types of communication technologies will be employed by particular agencies and departments responding to an emergency. Accordingly, this system cannot quickly adapt to the unpredictable requirements of emergency situations. In order to avoid this problem an emergency agency must purchase every conceivable type of interface module, which can be an unnecessary expense when some of these modules are never actually needed. Another problem with the ACU-1000 is that each interface module includes its own radio interface circuitry (e.g., duplexers, filters, preamplifiers, analog-to-digital converters, digital-to-analog converters, upconverters and downconverters) and requires separate antennas.
Vanu, Inc. of Cambridge Mass., provides the Vanu Anywave™ Base Station Subsystem (BSS), which is a software defined radio subsystem. This subsystem can be reprogrammed to enable arbitrary combinations of wireless communication technologies, such as iDEN, GSM and 1xRTT.